The Lone Lisp Heap

One coder built a language from scratch, and the comments instantly turned into therapy, flexing, and jokes

TLDR: A solo developer built not just a new Lisp-like language, but also the system that manages its memory from scratch. Commenters loved the honesty, with veterans sharing war stories and one deadpan joke about whether a “heap” should literally use a heap stealing the show.

A solo coder has posted a very raw, very personal look at building a programming language from the ground up — including the part where there was no built-in memory manager at all, so they just went ahead and made one. In plain English: this person didn’t just write the language, they also had to invent the system for handing out chunks of memory, then admit that the first version was clunky, wasteful, and very much a "learning in public" moment. That honesty is exactly what lit up the comment section.

The strongest reaction? A wave of battle-scarred veteran energy. One commenter basically delivered the universal creator’s curse: you learn a ton, then eventually realize you could redo the whole thing better. Another jumped in with a full-on flashback story about moving an old language system from Pascal to C, which gave the thread that classic internet vibe of "nice post, now let me tell you about the time I fought this dragon in 1997." It’s half support group, half subtle flex.

And then came the comic relief. One reader, clearly representing the civilians in the room, looked at the title and innocently asked whether a thing called a heap is supposed to use… a heap. Honestly? Iconic. That little joke-y misunderstanding gave the whole discussion a memeable twist: while experts reminisced about pain, everyone else was just trying to figure out whether the title had accidentally spoiled the ending. The mood is a mix of admiration, nostalgia, and gentle roasting — which, online, is basically a standing ovation.

Key Points

  • The article describes Lone's runtime as a tagged value system in C using enums and unions to represent types such as lists, vectors, and tables.
  • Lone was developed iteratively, with the language emerging alongside implementation of its virtual machine and runtime.
  • Because Lone is written in freestanding C, the project cannot rely on libc or malloc for dynamic memory allocation.
  • The custom allocator models memory blocks with metadata including size, free status, and links to previous and next blocks.
  • The allocator uses a first-fit search and is then improved by splitting oversized blocks into a requested allocation and a remaining free block.

Hottest takes

"you can go back and do it all better" — PaulHoule
"Flashbacks to when I implemented a new storage system" — NetMageSCW
"based on the name I assumed that you should use a heap" — dullcrisp
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